1. Field of the Invention
This invention concerns deep-well-drilling operations, in general, and more particularly relates to a system for improving the sensitivity of hook-load measurements.
2. Description of the Prior Art
In deep-well-drilling operations, in particular, it has been found that the load variations on the hook of the derrick are of such amplitude, in the total range thereof, as to make the measurements which are desired quite insensitive. For example, the conventional recording scale hook load measurement employs about 1,000 pounds per line of the cable pulley system per chart division. This results in 8,000 to 12,000 pounds per division of the chart scale. Consequently, small changes in weight on the hook are not visible in the resulting recording of such weight under the conventional measuring systems.
It is an object of this invention to provide an increase in the sensitivity of the system in order to be able to observe and/or record the changes in load that are relatively small compared to those previously possible.